C 6B
  • C921600
  • DE 29323089


These reference speakers in our C-series raise the bar to a new level of fantastic sound quality. The legendary sisal woofer cones are equipped with an additional structural damping layer made of an elastomer, which again improves the acoustic properties of the driver. The tweeter enclosure also underwent a complete overhaul. Anyone who wants to operate these loudspeakers as fully active speakers (e.g. using our new digital signal processors) can put together the system of their choice by combining the individual components.


  • High-end mid-woofer with sturdy aluminum diecast basket
  • Mid-woofer cone with scooped, long-fibered sisal with additional elastomer structural damping
  • Virtually compression-free conversion of the amplifier power into sound pressure
  • Lowest manufacturing tolerances and exclusive use of selected materials
  • Grille included

Technical data

Power RMS / max.  P 150 / 300 Watts
Impedance  Z 4 Ω
DC resistance  Re 3.4 Ω
Resonance frequency  Fs 54 Hz
Mechanical Q factor  Qms 11.1
Electrical Q factor  Qes 0.55
Total Q factor Qts 0.53
Compliance Cms 490 µm/N
Equivalent air volume Vas 12.4 L
Force factor  B*I 6.1 Tm
Efficiency 1 W / 1 m SPL 88 dB
Cone area  Sd 135 cm²
Moving mass  Mms 17.8 g
Cone material   Sisal with elastomer structural damping
Mechanical resistance  Rms 0.54 kg/s
Voice coil diameter ø 37 mm 
Voice coil winding height   12 mm
Max. linear excursion  Xmax +/- 3 mm
Outer diameter ø 166 mm / 6.54"
Installation diameter ø 145 mm / 5.71"
Installation depth   67 mm / 2.64"
Recommended enclosure volumes  
Sealed box  
Net volume   8 L
Lower limiting frequency (-3dB)   68 Hz
Vented box  
Net volume   15 L
Port diameter ø 60 mm / 2.36"
Port area   28 cm²
Port length   16 cm / 6.30"
Port tuning frequency Fb 49 Hz
Lower limiting frequency (-3dB)   52 Hz

Scope of delivery

2 x High-end mid-woofer HELIX C 6B
2 x Mounting ring
2 x Grille

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